Circuit structure of bar code reader capable of reading bar code with decreased power consumption

Abstract

A bar code reader is provided which is designed to read a bar code with a decreased power consumption. The bar code reader includes a laser output cycle adjuster that determines a laser output cycle consisting of a laser on-duration in which a laser source is allowed to emit a laser beam and a laser off-duration in which the laser source is inhibited from emitting the laser beam. This prevents the laser beam from being outputted continuously when the bar code reader is distant from the bar code, and it is difficult to read the bar code correctly, thereby minimizing a power waste in the bar code reader.

What is claimed is: 
     
       1. A bar code reader comprising: a laser source that emits a laser beam;   a laser output cycle determining circuit that determines a laser output cycle consisting of a laser on-duration in which the laser source is allowed to emit the laser beam and a laser off-duration in which said laser source is inhibited from emitting the laser beam;   a scanner that scans a bar code using the laser beam emitted from said laser source to pick up bars and spaces between the bars of the bar code within the laser on-duration of the laser output cycle;   a code converting circuit that converts the bars and the spaces picked up by said scanner into numerical codes; and   a decoding circuit that decodes the numerical codes provided by said code converting circuit to produce bar code information.   
     
     
       2. A bar code reader as set forth in claim 1, wherein said laser output cycle determining circuit is designed to change the laser output cycle in response to a signal provided manually. 
     
     
       3. A bar code reader as set forth in claim 1, wherein said laser output cycle determining circuit is designed to change the laser output cycle automatically according to a change in number of the numerical codes derived by said code converting circuit. 
     
     
       4. A bar code reader as set forth in claim 1, further comprising a shock sensor which senses contact of the bar code reader with an article with a bar code label on which the bar code is printed to turn on the bar code reader. 
     
     
       5. A bar code reader as set forth in claim 4, further comprising a switch designed to activate the bar code reader in response to a manually provided turn-on signal. 
     
     
       6. A bar code reader as set forth in claim 1, further comprising a code number comparing circuit that compares the number of the numerical codes derived by said code converting circuit with a reference number, when the number of the numerical codes is smaller than the reference number, said code number comparing circuit providing a decoding inhibit signal to inhibit said decoding circuit from decoding the numerical codes, when the number of the numerical codes is greater than or equal to the reference number, said code number comparing circuit providing a decoding enable signal to allow said decoding circuit to decode the numerical codes. 
     
     
       7. A bar code reader as set forth in claim 6, further comprising a reference number adjusting circuit that changes the reference number. 
     
     
       8. A bar code reader as set forth in claim 6, further comprising a scan cycle detecting circuit that outputs a scan cycle signal at each start of scan cycles of said scanner and a controlling circuit that prohibits said code converting circuit from converting the bars and the spaces picked up by said scanner into the numerical codes in response to first one of the scan cycle signals outputted from said scan cycle detecting circuit after said code number comparing circuit provides the decoding enable signal to allow said decoding circuit to decode the numerical codes. 
     
     
       9. A bar code reader, comprising: a laser source that emits a laser beam;   a scanner that scans a bar code using the laser beam emitted from said laser source to pick up bars and spaces between the bars of the bar code;   a code converting circuit that converts the bars and spaces picked up by said scanner into numerical codes, said code converting circuit also determining the number of numerical codes;   a code number comparing circuit that compares the number of numerical codes determined bv said code converting circuit with a small reference number, when the number of the numerical codes is smaller than the reference number said code number comparing circuit providing a decoding inhibit signal, and when the number of the numerical codes is greater than or equal to the reference number, said code number comparing circuit providing a decoding enable signal;   a decoding circuit that is responsive to the decoding enable signal provided by said code number comparing circuit to decode the numerical codes and output signals indicative thereof, said decoding circuit being inhibited from decoding the numerical codes in response to the decoding inhibit signal; and,   a laser output cycle determining circuit that determines a laser output cycle comprising a laser on-duration in which said laser source is allowed to emit the laser beam and a laser off-duration in which said laser source is inhibited from emitting the laser beam.   
     
     
       10. A bar code reader as set forth in claim 9, wherein said laser output cycle determining circuit is designed to change the laser output cycle in response to a signal provided manually. 
     
     
       11. A bar code reader as set forth in claim 9, wherein said laser output cycle determining circuit is designed to change the laser output cycle automatically according to a change in number of the numerical codes derived by said code converting circuit. 
     
     
       12. A bar code reader as set forth in claim 9, further comprising a shock sensor which senses contact of the bar code reader with an article with a bar code label on which the bar code is printed to turn on the bar code reader. 
     
     
       13. A bar code reader as set forth in claim 12, further comprising a switch designed to activate the bar code reader in response to a manually provided turn-on signal.